feat(macro): throw useful error message if macro used without a plugin

packages/macro/src/index.ts

@@ -27,27 +27,41 @@ const getSymbolSource = (name: 'i18n' | 'Trans'): [source: string, identifier?:
 const [i18nImportModule, i18nImportName = "i18n"] = getSymbolSource("i18n")
 const [TransImportModule, TransImportName = "Trans"] = getSymbolSource("Trans")
 
+const jsMacroTags = new Set([
+  'defineMessage',
+  'arg',
+  't',
+  'plural',
+  'select',
+  'selectOrdinal'
+])
+
+const jsxMacroTags = new Set([
+  'Trans',
+  'Plural',
+  'Select',
+  'SelectOrdinal',
+])
+
 function macro({ references, state, babel }: MacroParams) {
   const jsxNodes: NodePath[] = []
   const jsNodes: NodePath[] = []
   let needsI18nImport = false
 
   Object.keys(references).forEach((tagName) => {
     const nodes = references[tagName]
-    const macroType = getMacroType(tagName)
-    if (macroType == null) {
-      throw nodes[0].buildCodeFrameError(`Unknown macro ${tagName}`)
-    }
 
-    if (macroType === "js") {
+    if (jsMacroTags.has(tagName)) {
       nodes.forEach((node) => {
         jsNodes.push(node.parentPath)
       })
-    } else {
+    } else if(jsxMacroTags.has(tagName)) {
       nodes.forEach((node) => {
         // identifier.openingElement.jsxElement
         jsxNodes.push(node.parentPath.parentPath)
       })
+    } else {
+      throw nodes[0].buildCodeFrameError(`Unknown macro ${tagName}`)
     }
   })
 
@@ -131,21 +145,15 @@ const alreadyVisited = (path: NodePath) => {
   }
 }
 
-function getMacroType(tagName: string): string {
-  switch (tagName) {
-    case "defineMessage":
-    case "arg":
-    case "t":
-    case "plural":
-    case "select":
-    case "selectOrdinal":
-      return "js"
-    case "Trans":
-    case "Plural":
-    case "Select":
-    case "SelectOrdinal":
-      return "jsx"
-  }
-}
+[...jsMacroTags, ...jsxMacroTags].forEach((name) => {
+  Object.defineProperty(module.exports, name, {
+    get() {
+      throw new Error(`The macro you imported from "@lingui/macro" is being executed outside the context of compilation with babel-plugin-macros. `
+        + `This indicates that you don't have the babel plugin "babel-plugin-macros" configured correctly. `
+        + `Please see the documentation for how to configure babel-plugin-macros properly: `
+        + 'https://github.com/kentcdodds/babel-plugin-macros/blob/main/other/docs/user.md');
+    }
+  })
+})
 
 export default createMacro(macro)

packages/macro/test/index.ts

@@ -28,6 +28,8 @@ const testCases: Record<string, TestCase[]> = {
 }
 
 describe("macro", function () {
+  process.env.LINGUI_CONFIG = path.join(__dirname, "lingui.config.js")
+
   const babelOptions: TransformOptions = {
     filename: "<filename>",
     configFile: false,
@@ -54,7 +56,16 @@ describe("macro", function () {
 
       cases.forEach(
         (
-          { name, input, expected, filename, production, useTypescriptPreset, only, skip },
+          {
+            name,
+            input,
+            expected,
+            filename,
+            production,
+            useTypescriptPreset,
+            only,
+            skip,
+          },
           index
         ) => {
           let run = it
@@ -73,8 +84,6 @@ describe("macro", function () {
               babelOptions.presets.push("@babel/preset-typescript")
             }
 
-            process.env.LINGUI_CONFIG = path.join(__dirname, "lingui.config.js")
-
             try {
               if (filename) {
                 const inputPath = path.relative(
@@ -111,6 +120,17 @@ describe("macro", function () {
     })
   })
 
+  it("Should throw error if used without babel-macro-plugin", async () => {
+    await expect(
+      async () => {
+        const mod = await import("../src/index");
+        return (mod as unknown as typeof import('@lingui/macro')).Trans
+      }
+    ).rejects.toThrow(
+      'The macro you imported from "@lingui/macro"'
+    )
+  })
+
   describe.skip("validation", function () {
     describe("plural/select/selectordinal", function () {
       it("value is missing", function () {